Disc recording medium, disc drive apparatus, reproduction method, and disc manufacturing method

ABSTRACT

A recording and reproducing area and a reproduction-only area are formed by wobbling a groove formed in a spiral fashion to form a track to be tracked on a disk. The recording and reproducing area has address information recorded by wobbling of the groove and information recorded and reproduced by phase change marks on the track formed by the groove where the address information is recorded. The reproduction-only area has prerecorded information recorded by wobbling of the groove.

TECHNICAL FIELD

The present invention relates to a disk recording medium such as anoptical disk or the like, a disk manufacturing method for manufacturingthe disk recording medium, and a disk drive apparatus and a reproducingmethod for the disk recording medium, and particularly to a disk havinga track wobbled as a pregroove.

BACKGROUND ART

As technology for recording and reproducing digital data, there is adata recording technology using optical disks (including magneto-opticaldisks) such for example as CD (Compact Disk), MD (Mini-Disk), and DVD(Digital Versatile Disk) for recording media. The optical disk is ageneric term for recording media that are disks having a metallic thinplate protected with plastic and irradiated with laser light to read asignal through change in the reflected light.

Optical disks for example include reproduction-only types known as CD,CD-ROM, DVD-ROM and the like and user data recordable types known as MD,CD-R, CD-RW, DVD-R, DVD−RW, DVD+RW, DVD-RAM and the like. The recordabletypes allow data to be recorded thereon by using a magneto-opticrecording method, a phase change recording method, a dye film changerecording method and the like. The dye film change recording method isalso referred to as a write-once recording method, which allows datarecording only once and does not allow rewriting. The dye film changerecording method is therefore suitable for data storing purposes and thelike.

On the other hand, the magneto-optic recording method and the phasechange recording method allow data rewriting, and are used for variouspurposes including recording of various contents data such as music,video, games, application programs and the like.

To record data on a recordable disk by the magneto-optic recordingmethod, the dye film change recording method, the phase change recordingmethod or the like requires guiding means for tracking a data track.Thus, a groove is formed in advance as a pregroove, and the groove or aland (a portion of trapezoidal cross section sandwiched between grooves)is used as a data track.

It is also necessary to record address information so that data can berecorded at predetermined positions on the data track. The addressinformation may be recorded by wobbling the groove.

Specifically, the track for recording data is formed in advance as apregroove, for example, and side walls of the pregroove are wobbled incorrespondence with the address information.

This makes it possible to read addresses from wobbling informationobtained as reflected light information at the time of recording andreproduction and therefore record and reproduce data at desiredpositions even when for example pit data or the like indicatingaddresses is not formed in advance on the track.

Thus adding the address information as a wobbling groove eliminates theneed for providing for example discrete address areas on the track andrecording addresses as pit data, for example. Since the address areasare not required, real data recording capacity can be correspondinglyincreased. Incidentally, absolute time (address) information representedby such a wobbled groove is referred to as ATIP (Absolute Time InPregroove) or ADIP (Adress In Pregroove).

Recently, it has become necessary to record various information on thedisk in advance, as with the address information, in addition to theaddress information and information recorded and reproduced by the user.

Specifically, as prerecorded information recorded on the disk inadvance, disk information indicating conditions for recording on thedisk, for example a recording linear velocity, a recommended value oflaser power and the like, and copy protect information for excludinghacked apparatus and the like are desired to be recorded. The copyprotect information is particularly important.

A known method for prerecording various information on the disk is toform embossed pits on the disk.

Considering high-density recording and reproduction on an optical disk,however, the method of prerecording by embossed pits is disadvantageous.

High-density recording and reproduction on an optical disk requires areduction in groove depth. In the case of a disk having a groove andembossed pits produced simultaneously by a stamper, it is very difficultto make depth of the groove and depth of the embossed pits differentfrom each other. Thus, the depth of the embossed pits has to be the sameas the depth of the groove.

However, when the depth of the embossed pits is reduced, a signal ofgood quality cannot be obtained from the embossed pits.

For example, a volume of 23 GB (gigabytes) can be recorded andreproduced on an optical disk 12 cm in diameter by recording andreproducing phase change marks at a track pitch of 0.32 μm and a lineardensity of 0.12 μm/bit on a disk having a cover (substrate) thickness of0.1 mm, using a laser diode having a wavelength of 405 nm and anobjective lens having an NA=0.85 as an optical system.

In this case, the phase change marks are recorded and reproduced on agroove formed in a spiral fashion on the disk. In order to suppressmedia noise for higher density, a groove depth of about 20 nm, that is,1/13 to 1/12 of a wavelength λ is desirable.

In order to obtain a signal of good quality from embossed pits, on theother hand, a depth of the embossed pits is desired to be λ/8 to λ/4.After all, a good solution as a common depth of the groove and theembossed pits has not been obtained.

Because of such a situation, a method of prerecording information byother than embossed pits is desired.

Disclosure of Invention

On a disk recording medium according to the present invention, arecording and reproducing area and a reproduction-only area are formedby wobbling a groove formed in a spiral fashion to form a track to betracked on the disk. The recording and reproducing area has addressinformation recorded by wobbling of the groove and information recordedand reproduced by phase change marks on the track formed by the groovewhere the address information is recorded. The reproduction-only areahas prerecorded information recorded by wobbling of the groove.

This eliminates the need for recording the prerecorded information byembossed pits. Since it is not necessary to form embossed pits, thedepth of the groove can be reduced. That is, the depth of the groove canbe set to an optimum state for high-density recording without regard forreproduction characteristics of the embossed pits. Thus high-densityrecording that realizes a capacity of 23 GB or the like on a disk 12 cmin diameter, for example, is made possible.

A disk drive apparatus can reproduce the prerecorded information(extract wobble information) by the same wobble channel reproducingsystem for the address information (ADIP).

Further, by recording copy protect information as the prerecordedinformation by the wobbling groove instead of forming embossed pits, itis possible to construct a storage system suitable as a system forrecording and reproducing a video signal, an audio signal and the like.

The reproduction-only area does not have information recorded by phasechange marks. Since phase change marks can be said to convert highreflectivity of a recording layer into low reflectivity, a track havingphase change marks recorded thereon is decreased in averagereflectivity. That is, returned light is reduced, which isdisadvantageous in terms of SNR (Signal Noise Ratio) for extraction of awobbling component of the groove. According to the present invention, bynot recording phase change marks in the reproduction-only area, it ispossible to prevent degradation in the SNR of the prerecordedinformation and thereby obtain a wobbling signal of good quality.

Further, linear density of the prerecorded information recorded in thereproduction-only area is lower than linear density of the informationrepresented by phase change marks in the recording and reproducing areaand is higher than linear density of the address information in therecording and reproducing area.

By making the recording linear density of the prerecorded informationlower than the recording linear density of the phase change marks, it ispossible to reproduce with good quality a wobbling signal that isobtained from a push-pull signal and is inferior in SNR to the phasechange marks.

Further, by making the recording linear density of the prerecordedinformation higher than the linear density of the address information(ADIP), it is possible to raise a transfer rate and shorten reproductiontime.

The prerecorded information is modulated by an FM code and recorded. Itis thereby possible to narrow a band of the signal and thus improve theSNR. Further, both a PLL and a detection circuit can be formed by simplehardware.

An ECC (error correction code) format of the prerecorded informationuses the same code and structure as an ECC format of the informationrecorded by phase changes. Thus the same hardware can be used for ECCprocessing of the prerecorded information and the phase changeinformation, thereby promoting a reduction in cost of the disk driveapparatus and simplification of configuration of the disk driveapparatus.

Error correction code including address information is added to theprerecorded information. The disk drive apparatus can thereby performaccess/reproduction operation properly on the basis of the address inthe reproduction-only area.

A synchronizing signal of the prerecorded information has a plurality ofsynchronizing signals. Each of the synchronizing signals comprises apattern out of rules of modulation of the information and anidentification pattern for identifying the synchronizing signal. Theidentification pattern is obtained by modulating an identificationnumber and an even parity bit of the identification number by an FMcode.

This makes it easier to determine the position of each of thesynchronizing signals even in the middle of an ECC block and detect anaddress within the ECC block. When identifying each synchronizing signalpattern among a plurality of synchronizing signal patterns, thesynchronizing signal pattern is identified by difference in theidentification pattern, and also a parity check is performed, wherebythe identification pattern can be checked for correctness and thus eachof the synchronizing signals can be identified with higher accuracy.

Thus, the present invention is suitable for a large-capacity diskrecording medium, and great effects are obtained in that the disk driveapparatus is improved in recording and reproducing operation performanceand the wobble processing circuit system may be a simple one.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1A is a diagram of assistance in explaining a groove of a diskaccording to an embodiment of the present invention, and FIG. 1B is adiagram of assistance in explaining wobbling of the groove;

FIG. 2 is a diagram of assistance in explaining an area structure of thedisk according to the embodiment;

FIG. 3A is a diagram of assistance in explaining a method of wobbling agroove in a track of an RW zone of the disk according to the embodiment,and FIG. 3B is a diagram of assistance in explaining a method ofwobbling a groove in a track of a PB zone;

FIGS. 4( a) to 4(k) are diagrams of assistance in explaining a method ofmodulation of prerecorded information according to the embodiment;

FIGS. 5A to 5D are diagrams of assistance in explaining an ECC structureof phase change marks according to the embodiment;

FIGS. 6A to 6D are diagrams of assistance in explaining an ECC structureof prerecorded information according to the embodiment;

FIG. 7A is a diagram of assistance in explaining a frame structure ofmain data in the RW zone according to the embodiment, and FIG. 7B is adiagram of assistance in explaining a frame structure of the prerecordedinformation in the PB zone;

FIG. 8 is a diagram of assistance in explaining frame syncs of theprerecorded information according to the embodiment;

FIG. 9 is a diagram of assistance in explaining a frame sync arrangementof the prerecorded information according to the embodiment;

FIG. 10A is a diagram of assistance in explaining address fields in aBIS of the prerecorded information according to the embodiment, and FIG.10B is a diagram of assistance in explaining user control data;

FIG. 11 is a diagram of assistance in explaining a BIS structure of theprerecorded information according to the embodiment;

FIG. 12 is a diagram of assistance in explaining a BIS structure of theprerecorded information according to the embodiment;

FIG. 13 is a diagram of assistance in explaining a BIS structure of theprerecorded information according to the embodiment;

FIG. 14 is a diagram of assistance in explaining an address unit of theprerecorded information according to the embodiment;

FIGS. 15A, 15B, and 15C are diagrams of assistance in explaining amethod of modulation of ADIP information according to the embodiment;

FIGS. 16A and 16B are diagrams of assistance in explaining addressblocks in a RUB according to the embodiment;

FIGS. 17A and 17B are diagrams of assistance in explaining a sync partof the disk according to the embodiment;

FIGS. 18A to 18E are diagrams of assistance in explaining sync bitpatterns of the disk according to the embodiment;

FIGS. 19A and 19B are diagrams of assistance in explaining a data partof the disk according to the embodiment;

FIGS. 20A, 20B, and 20C are diagrams of assistance in explaining ADIPbit patterns of the disk according to the embodiment;

FIG. 21 is a diagram of assistance in explaining an ECC structure of theADIP information according to the embodiment;

FIG. 22 is a block diagram of a disk drive apparatus according to theembodiment;

FIG. 23 is a block diagram of an MSK demodulation unit of the disk driveapparatus according to the embodiment;

FIGS. 24A to 24G are diagrams of assistance in explaining MSKdemodulation processing of the disk drive apparatus according to theembodiment; and

FIG. 25 is a block diagram of a cutting apparatus for producing the diskaccording to the embodiment.

BEST MODE FOR CARRYING OUT THE INVENTION

An optical disk according to an embodiment of the present invention willhereinafter be described, and also a disk drive apparatus (recording andreproducing apparatus) and a manufacturing method provided for theoptical disk will be described in the following order.

1. Disk

1-1. Physical Characteristics of Optical Disk

1-2. Prerecorded Information

1-3. ADIP Address

2. Disk Drive Apparatus

3. Disk Manufacturing Method

1. Disk

1-1. Physical Characteristics of Optical Disk

Physical characteristics of a disk according to the embodiment and awobbling track will first be described.

The optical disk in this example belongs to a category of disks recentlydeveloped under a name of DVR (Data&Video Recording) disks, for example,and particularly has a new wobbling system as a DVR system.

Data is recorded on the optical disk in this example by a phase changemethod. As to disk size, the optical disk is 120 mm in diameter. Theoptical disk has a disk thickness of 1.2 mm. Thus, in these respects,the optical disk is similar to a disk of a CD (Compact Disc) type and adisk of a DVD (Digital Versatile Disc) type in terms of outwardappearance.

Laser wavelength for recording/reproduction is 405 nm. A so-called bluelaser is used. An NA of the optical system is 0.85.

A track where phase change marks are recorded has a track pitch of 0.32μm and a linear density of 0.12 μm.

As a user data capacity, about 23 Gbytes is realized.

Data is recorded by a groove recording method. That is, a track ispreformed by a groove on the disk, and recording is performed in thegroove.

As schematically shown in FIG. 1A, a groove GV is formed in a spiralfashion from an innermost circumference to an outermost circumference onthe disk. Incidentally, as another example, the groove GV can be formedconcentrically.

While the disk is driven to be rotated by a CLV (constant linearvelocity) method for recording and reproduction of data, CLV is alsoapplied to the groove GV. Hence, the number of wobbling waves of agroove for one round of the track is increased toward the outercircumference of the disk.

A physical address is represented by forming such a groove GV in awobbling manner as shown in FIG. 1B.

That is, a right and a left side wall of the groove GV wobble incorrespondence with a signal generated on the basis of an address or thelike.

A land L is formed between the groove GV and an adjacent groove GV. Asdescribed above, data is recorded in the groove GV. That is, the grooveGV forms a data track. Incidentally, the land L may be used as a datatrack to record data on the land L, or both the groove GV and the land Lmay be used as a data track.

FIG. 2 shows a layout (area arrangement) of a disk as a whole.

As areas on the disk, a read-in zone, a data zone, and a read-out zoneare arranged from an inner circumference side.

In terms of area arrangement regarding recoding and reproduction, aninner circumference side of the read-in zone is a PB zone(reproduction-only area) and an area from an outer circumference side ofthe read-in zone to the read-out zone is an RW zone (recording andreproduction area).

The read-in zone is situated within a radius of 24 mm. A prerecordeddata zone is situated from a radius of 22.3 mm to a radius of 23.1 mm.

In the prerecorded data zone, information used for copy protection andthe like (prerecorded information) are recorded in advance by wobbling agroove formed on the disk in a spiral fashion. This information is notrewritable and is for reproduction only. That is, the prerecorded datazone forms the above-mentioned PB zone (reproduction-only area).

As the prerecorded information in the prerecorded data zone, copyprotection information is recorded, for example. The copy protectioninformation is used as follows, for example.

An optical disk system according to the present embodiment has a mediakey or a drive key indicating that a registered drive apparatus maker ordisk maker can do business and that the maker is registered.

In a case of hacking, the drive key or the media key is recorded as copyprotection information. This information can prevent media or a drivehaving the media key or the drive key from recording and reproduction.

In the read-in zone, a test write area and a defect management area areprovided from a radius of 23.1 mm to a radius of 24 mm.

The test write area is used for test write and the like in settingconditions for recording and reproducing phase change marks, such aslaser power at the time of recording/reproduction.

In the defect management area, information managing defect informationon the disk is recorded and reproduced.

The data zone is formed from a radius of 24.0 mm to a radius of 58.0 mm.The data zone is an area where user data is actually recorded andreproduced by phase change marks.

The read-out zone is formed from a radius of 58.0 mm to a radius of 58.5mm. A defect management area similar to that of the read-in zone isprovided in the read-out zone, and the read-out zone is used as a bufferarea to allow overrunning at the time of a seek.

An area from the radius of 23.1 mm, that is, the test write area to theread-out zone is the RW zone (recording and reproduction area) wherephase change marks are recorded and reproduced.

FIG. 3A shows wobbling of a groove in a track of the RW zone, and FIG.3B shows wobbling of a groove in a track of the PB zone.

In the RW zone, address information (ADIP) is formed in advance bywobbling the groove formed in a spiral fashion for tracking on the disk.

Information is recorded and reproduced by phase change marks in thegroove where the address information is formed.

As shown in FIG. 3A, the groove in the RW zone, that is, the groovetrack where the ADIP address information is formed has a track pitchTP=0.32 μm.

Recording marks formed by phase change marks are recorded on the track.The phase change marks are recorded at a linear density of 0.12 μm/bitor 0.08 μm/ch bit by an RLL (1, 7) PP modulation method (RLL; Run LengthLimited, PP: Parity preserve/Prohibit rmtr (repeated minimum transitionrunlength)) or the like.

Letting 1 T be 1 ch bit, length of a mark is 2 T to 8 T, and a minimummark length is 2 T.

The address information has a wobbling cycle of 69 T, and a wobblingamplitude WA of about 20 nm (p-p).

Frequency bands of the address information and the phase change marksare set so as not to coincide with each other, whereby each does notaffect detection of the other.

A CNR (carrier noise ratio) of wobbling of the address information is 30dB after recording at a bandwidth of 30 KHz, and an address error ratethereof is 1×10⁻³ or less, including effects of perturbations (diskskew, defocus, disturbances and the like).

On the other hand, the track formed by the groove in the PB zone in FIG.3B has a wider track pitch and a greater wobbling amplitude than thetrack formed by the groove in the RW zone in FIG. 3A.

Specifically, the track formed by the groove in the PB zone in FIG. 3Bhas a track pitch TP=0.35 μm, a wobbling cycle of 36 T, and a wobblingamplitude WA of about 40 nm (p-p) The wobbling cycle of 36 T indicatesthat recording linear density of the prerecorded information is higherthan recording linear density of the ADIP information. Further, sincethe minimum length of a phase change mark is 2 T, the recording lineardensity of the prerecorded information is lower than recording lineardensity of the phase change mark.

No phase change marks are recorded on the track of the PB zone.

A sinusoidal wobbling waveform is formed in the RW zone, whereas asinusoidal waveform or a rectangular waveform can be recorded in the PBzone.

It is known that phase change marks can be used for recording andreproduction of data because at a signal quality of a CNR of about 50 dBat a bandwidth of 30 KHz, a symbol error rate of 1×10⁻¹⁶ or less can beachieved after error correction by attaching ECC (error correction code)to the data for recording and reproduction.

A CNR of wobbles of the ADIP address information is 35 dB at a bandwidthof 30 KHz when phase change marks are not recorded yet.

This level of signal quality suffices for the address information byperforming interpolation protection on the basis of so-called continuitydetermination and the like. However, a signal quality of a CNR of 50 dBequal to that of the phase change marks or more is desired to beobtained for the prerecorded information recorded in the PB zone. Thus,the groove physically different from the groove in the RW zone is formedin the PB zone, as shown in FIG. 3B.

First, the track pitch is widened to thereby prevent a crosstalk from anadjacent track and the wobble amplitude is doubled, whereby the CNR canbe improved by +6 dB.

Then, the CNR can be improved by +2 dB by using a rectangular wobblewaveform.

In total, the CNR is 43 dB.

A difference in recording band between the phase change marks and thewobbles in the prerecorded data zone is represented by the wobbles of 18T (18 T is half of 36 T) and the phase change marks of 2 T. At thispoint, 9.5 dB is obtained.

Thus the CNR of the prerecorded information is equal to 52.5 dB. Evenwhen −2 dB is estimated as a result of a crosstalk from an adjacenttrack, the CNR is equal to 50.5 dB. That is, substantially the samelevel of signal quality as that of the phase change marks is achieved,and it is therefore appropriate enough to use a wobbling signal torecord and reproduce the prerecorded information.

1-2. Prerecorded Information

FIGS. 4( a) to 4(k) illustrate a method of modulation of the prerecordedinformation for forming the wobbling groove in the prerecorded datazone.

The modulation uses FM code.

FIG. 4( a) shows data bits, FIG. 4( b) shows channel clocks, FIG. 4( c)shows FM codes, and FIG. 4( d) shows wobble waveforms, the data bits,the channel clocks, the FM codes, and the wobble waveforms beingarranged vertically.

One bit of data is 2 ch (2 channel clocks). When bit information is “1,”the FM code has 1.2 of frequency of the channel clocks.

When bit information is “0,” the FM code is represented by ½ thefrequency of the bit information “1.”

As a wobble waveform, a rectangular wave of the FM code may be directlyrecorded, while a sinusoidal waveform may be recorded as shown in FIG.4( d).

Incidentally, the FM code and the wobble waveform may have patterns asshown in FIGS. 4( e) and 4(f) as patterns of opposite polarity fromthose of FIGS. 4( c) and 4(d).

Under such rules of FM code modulation, an FM code waveform and a wobblewaveform (sinusoidal waveform) when a data bit stream is “10110010” asshown in FIG. 4( g) are as shown in FIGS. 4( h) and 4(i).

Incidentally, an FM code waveform and a wobble waveform corresponding tothe patterns as shown in FIGS. 4( e) and 4(f) are as shown in FIGS. 4(j) and 4(k).

Referring to FIGS. 5A to 5D, FIGS. 6A to 6D, and FIGS. 7A and 7B, ECCformats of phase change marks and prerecorded information will bedescribed.

First, FIGS. 5A, to 5D show the ECC format of main data (user data)recorded and reproduced by phase change marks.

As ECC (error correction code), there are two codes, that is, LDC (longdistance code) for main data of 64 KB (=2048 bytes per sector×32sectors) and BIS (burst indicator subcode).

The main data of 64 KB shown in FIG. 5A is ECC-encoded as shown in FIG.5B. That is, an EDC (error detection code) of 4 B is added to one sectorof 2048 B of the main data, and LDC is encoded for the 32 sectors. TheLDC is an RS (reed solomon) (248, 216, 32) code with a code length of248, data of 216, and a distance of 32. There are 304 code words.

On the other hand, BIS is ECC-encoded as shown in FIG. 5D for data of720 B shown in FIG. 5C. Specifically, the BIS is an RS (reed solomon)(62, 30, 32) code with a code length of 62, data of 30, and a distanceof 32. There are 24 code words.

FIG. 7A shows a frame structure of the main data in the RW zone.

The LDC data and the BIS form the frame structure shown in the figure.Specifically, data (38 B), BIS (1 B), data (38 B), BIS (1 B), and data(38 B) are arranged per frame to form a structure of 155 B. That is, oneframe is formed by data of 38 B×4, or 152 B, and BIS of 1 B insertedafter each 38 B.

A frame sync FS (frame synchronizing signal) is disposed at the front ofone frame of 155 B. One block has 496 frames.

The LDC data has a 0th, a 2^(nd), . . . even-numbered code word placedin a 0^(th), a 2^(nd), . . . even-numbered frame and a 1^(st), a 3^(rd),. . . odd-numbered code word placed in a 1^(st), a 3^(rd), . . .odd-numbered frame.

BIS uses a code much superior to a code of LDC in correction capability.Almost all is corrected. That is, a code with a distance of 32 for acode length of 62 is used.

Thus, BIS symbols when errors are detected can be used as follows.

In ECC decoding, BIS is decoded first. When two adjacent to each otherof BISs and a frame sync FS in the frame structure of FIG. 7A have anerror, data of 38 B sandwiched between the two is considered to be aburst error. An error pointer is added to the data of 38 B. With LDC,this error pointer is used to make pointer erasure correction.

Thereby correction capability can be enhanced as compared withcorrection with only LDC. BIS includes address information and the like.The address is used for example when there is no address information inthe form of a wobbling groove on a ROM type disk or the like.

Next, FIGS. 6A, to 6D show the ECC format of prerecorded information.

In this case, as ECC, there are two codes, that is, LDC (long distancecode) for main data of 4 KB (=2048 B per sector×2 sectors) and BIS(burst indicator subcode).

The data of 4 KB as prerecorded information shown in FIG. 6A isECC-encoded as shown in FIG. 6B. That is, an EDC (error detection code)of 4 B is added to one sector of 2048 B of the main data, and LDC isencoded for the 2 sectors. The LDC is an RS (reed solomon) (248, 216,32) code with a code length of 248, data of 216, and a distance of 32.There are 19 code words.

On the other hand, BIS is ECC-encoded as shown in FIG. 6D for data of120 B shown in FIG. 6C. Specifically, the BIS is an RS (reed solomon)(62, 30, 32) code with a code length of 62, data of 30, and a distanceof 32. There are four code words.

FIG. 7B shows a frame structure of the prerecorded information in the PBzone.

The LDC data and the BIS form the frame structure shown in the figure.Specifically, a frame sync FS (1 B), data (10 B), BIS (1 B), and data (9B) are arranged per frame to form a structure of 21 B. That is, oneframe is formed by data of 19 B and inserted BIS of 1 B.

A frame sync FS (frame synchronizing signal) is disposed at the front ofone frame. One block has 248 frames.

Also in this case, BIS uses a code much superior to a code of LDC incorrection capability, and almost all is corrected. Thus, BIS symbolswhen errors are detected can be used as follows.

In ECC decoding, BIS is decoded first. When two adjacent to each otherof BISs and a frame sync FS have an error, data of 10 B or 9 Bsandwiched between the two is considered to be a burst error. An errorpointer is added to the data of 10 B or 9 B. With LDC, this errorpointer is used to make pointer erasure correction.

Thereby correction capability can be enhanced as compared withcorrection with only LDC.

BIS includes address information and the like. In the prerecorded datazone, prerecorded information is recorded by a wobbling groove and hencethere is no address information formed by a wobbling groove. Thus anaddress in the BIS is used for access.

As is understood from FIGS. 5A to 5D and FIGS. 6A, to 6D, the same codeand structure are used as the ECC format for the data represented byphase change marks and the prerecorded information.

This means that processing for ECC decoding of the prerecordedinformation can be performed by a circuit system for performing ECCdecoding processing at the time of reproduction of the data representedby phase change marks, and that efficiency of configuration of hardwareas the disk drive apparatus can be increased.

FIG. 8 shows frame syncs in the prerecorded data zone.

As frame sync FS, there are seven kinds of frame syncs FS0 to FS6. Eachof the frame syncs FS0 to FS6 is formed by a total of 16 channel bits,that is, 8 channel bits of a sync body. “11001001” using a pattern outof the rules of FM code modulation and 8 channel bits of a sync ID foreach of the seven kinds of frame syncs FS0 to FS6.

When represented by data bits, the sync ID of a frame sync FS0, forexample, is represented by 3 bits “000” and 1 parity bit (0 in thiscase). This sync ID is subjected to FM code modulation to provide“10101010.”

Similarly, the other sync IDs are represented by 3 data bits and 1parity bit, and are subjected to FM code modulation.

At the time of recording, frame syncs FS are subjected to NRZIconversion and then recorded.

FIG. 9 shows a mapping of frame syncs.

The 248 frames of one ECC block of the prerecorded information shown inFIG. 7B are divided into eight address frames of 31 frames each.

Each of the address frames has a frame number 0 to 30. For the framenumber “0,” FS0 is used as a special frame sync not used as other framesyncs. The frame sync FS0 makes it possible to find the head of theaddress frames and perform address synchronization.

For the frame numbers “1” to “30,” frame syncs (FS1 to FS6) are disposedin order as shown in FIG. 9. This order of arrangement of the framesyncs allows the head of the address frames to be identified even whenthe frame sync FS0 at the head cannot be identified.

As described above, an address included in the BIS is used for access inthe prerecorded data zone.

FIG. 10A and FIG. 10B show information included in the BIS of an ECCblock in the prerecorded data zone.

The BIS information comprises addresses and user control data.

FIG. 10A shows address fields in the BIS. As addresses, there are eightaddress fields (#0 to #7) in one ECC block.

One address field is formed by 9 bytes. The address field #0, forexample, is formed by 9 bytes A0-0 to A0-8.

An address value indicating an ECC block address referred to as an AUN(address unit number) is disposed in 4 MSB bytes of each of the addressfields.

An address field number is disposed in 3 low-order bits (3 Lsbits) of a5th byte of each of the address fields.

Further, parity for each of the address fields is disposed in 4low-order bytes of the address field.

On the other hand, as shown in FIG. 10B, there are two units (#0 and #1)of user control data in a BIS within one ECC block.

One unit of user control data is formed by 24 bytes. The unit #0, forexample, is formed by 24 bytes UC0-0 to UC0-23.

The user control data is reserved for use by a future system.

FIG. 11 shows an arrangement of BIS information of the BIS, that is, theBIS cluster of the ECC block in the prerecorded data zone.

The BIS cluster comprises four correction codes. In FIG. 11, onlyinformation excluding parity is shown. The codes are formed in a columndirection of the figure. The BIS cluster is formed by four columns.

One column of information is formed by a total of 30 rows, that is, 18rows of addresses and 12 rows of user control data.

The addresses of the address fields #0 to #7 are arranged in aninterleaved manner in the four columns, as shown in FIG. 11. Althoughonly the address fields #0, #1, and #2 are shown in FIG. 11, the 9 bytesA0-0 to A0-8 comprising the address field #0, for example, are arrangedin positions shown as hatched portions in the figure.

The units #0 and #1 of user control data are each arranged in an area of12 rows as shown in FIG. 11.

At the time of recording, the address field #0 shown in FIG. 11, forexample, is recorded in an oblique direction of the BIS cluster so as tobe arranged sequentially.

FIG. 12 shows the whole BIS cluster including parity.

As described above, the error correction code of the BIS is an RS (62,30, 32) code. The BIS cluster has four codes with a code length of 62symbols, and one code is encoded in a vertical direction as shown by anarrow in FIG. 12.

FIG. 13 illustrates an order in which the 248 symbols of the BIS clusterincluding the parity are recorded.

At the time of recording, the BIS cluster is recorded as eight addressunits. One address unit is formed by 31 symbols, as shown in FIG. 14.

In first 9 bytes in each of the address units, 9 bytes (An-0 to An-8) asan address field #n corresponding to each address unit number aredisposed. For example, the address field #0 (A0-0 to A0-8) is disposedin an address unit 0.

The 31 symbols as such an address unit 0 are arranged as shown ashatched portions in FIG. 13, for example.

The 31 symbols of one address unit corresponds to the above-mentioned 31address frames. The frame numbers and the frame sync patterns (FS0 toFS6) in FIG. 9 make it possible to detect timing of one address unitfrom timing of the frame sync FS0 and thereby reproduce the addresses ofthe address fields (#0 to #7).

1-3. ADIP Address

Next, ADIP addresses recorded as a wobbling groove in the RW zone willbe described.

FIGS. 15A, 15B, and 15C illustrate MSK (minimum shift keying)modulation, one of FSK modulations, used as a method of modulation ofADIP addresses recorded by wobbling a groove.

Detection length (window length) of data is a unit of two wobblesections. One wobble section is a section of one cycle of a wobble at acarrier frequency.

Data such as addresses is subjected to differential encoding using onewobble as a unit before recording, as shown in FIGS. 15A and 15B.

Specifically, precoded data after differential encoding before recordingis “1” during one wobble period from a rising edge of data “1” to afalling edge.

As shown in FIG. 15C, an MSK stream obtained by MSK modulation of suchprecoded data is cosωt or −cosωt, which represents a carrier, when theprecoded data is “0.” When the precoded data is “1,” the MSK stream iscos1.5ωt or −cos1.5ωt, which represents 1.5 times the frequency of thecarrier.

As shown in FIG. 15C, letting 1 ch be length of 1 channel bit of phasechange data recorded and reproduced, a cycle of the carrier is 69 ch.

In the case of the present embodiment, three ADIP addresses are includedin one RUB (recording unit block: a recording and reproducing cluster)as a data recording unit.

FIG. 16 shows such a RUB. The RUB (recording and reproducing cluster) isa recording and reproducing unit as 498 frames obtained by adding a linkarea of 2 frames for a PLL or the like to a front and a rear of the 496frames of the ECC block of the data shown in FIG. 7A.

As shown in FIG. 16A, a section corresponding to one RUB includes threeaddress blocks as ADIP.

One address block is formed by 83 bits.

FIG. 16B shows a composition of one address block. The address block of83 bits comprises a sync part (synchronizing signal part) of 8 bits anda data part of 75 bits.

In the 8 bits of the sync part, four units of a sync block comprising amonotone bit (1 bit) and a sync bit (1 bit) are formed.

In the 75 bits of the data part, 15 units of an ADIP block comprising amonotone bit (1 bit) and ADIP bits (4 bits) are formed.

The monotone bits, the sync bit, and the ADIP bits are each formed by awobble having 56 wobble periods. An MSK mark for bit sync is disposed atthe head of these bits.

Following the MSK mark of a monotone bit, wobbles of the carrierfrequency are formed continuously. The sync bit and the ADIP bits, whichwill be described later, are formed with wobbles formed by MSK modulatedwaveforms following the MSK mark.

A composition of the sync part will first be described with reference toFIGS. 17A and 17B.

As is understood from FIGS. 17A and 17B, the sync part of 8 bits isformed by four sync blocks (sync blocks “0” “1,” “2,” and “3”). Each ofthe sync blocks is 2 bits.

The sync block “0” is formed by a monotone bit and a sync “0” bit.

The sync block “1” is formed by a monotone bit and a sync “1” bit.

The sync block “2” is formed by a monotone bit and a sync “2” bit.

The sync block “3” is formed by a monotone bit and a sync “3” bit.

The monotone bit in each of the sync blocks is a waveform of continuouswobbles of a single frequency representing the carrier, as describedabove. The monotone bit is shown in FIG. 18A. Specifically, an MSK markas a bit sync bs is attached to a start of the 56 wobble periods,followed by the continuous wobbles of the single frequency.

Incidentally, an MSK mark pattern is shown under wobble amplitude ineach of FIGS. 18A to 18E.

There are four kinds of sync bits ranging from the sync “0” bit to thesync “3” bit as described above.

The four kinds of sync bits are wobble patterns as shown in FIGS. 18B,18C, 18D, and 18E, respectively.

The sync “0” bit of FIG. 18B is a pattern where an MSK mark as a bitsync bs is followed by 16 wobble sections and then an MSK mark, andfurther by 10 wobble sections and then an MSK mark.

Each of the sync “1” bit to the sync “3” bit is a pattern formed byshifting the position of the MSK marks backward by two wobble sections.

Specifically, the sync “1” bit of FIG. 18C is a pattern where an MSKmark as a bit sync bs is followed by 18 wobble sections and then an MSKmark, and further by 10 wobble sections and then an MSK mark.

The sync “2” bit of FIG. 18D is a pattern where an MSK mark as a bitsync bs is followed by 20 wobble sections and then an MSK mark, andfurther by 10 wobble sections and then an MSK mark.

The sync “3” bit of FIG. 18E is a pattern where an MSK mark as a bitsync bs is followed by 22 wobble sections and then an MSK mark, andfurther by 10 wobble sections and then an MSK mark.

Each of the sync patterns is unique as distinct from the monotone bitand the ADIP bits to be described next. Thus the sync bits of the fourpatterns are disposed one in each of the sync blocks. The disk driveapparatus can achieve synchronization when the disk drive apparatus candetect one of the sync units of the four patterns from the sync partsection.

A composition of the data part in the address block will next bedescribed with reference to FIGS. 19A and 19B.

As is understood from FIGS. 19A and 19B, the data part comprises 15 ADIPblocks (ADIP blocks “0” to “14”). Each of the ADIP blocks is 5 bits.

Each of the 5-bit ADIP blocks comprises 1 monotone bit and 4 ADIP bits.

In each of the ADIP blocks, as in the case of the sync blocks, an MSKmark as a bit sync bs is attached to a start of 56 wobble periods of themonotone bit, followed by continuous wobbles of the carrier frequency.The monotone bit is shown in FIG. 20A.

Since one ADIP block includes 4 ADIP bits, 60 ADIP bits of the 15 ADIPblocks form address information.

Patterns of “1” and “0” as ADIP bits are shown in FIGS. 20B and 20C.

As shown in FIG. 20B, in the wobble waveform pattern when a value of anADIP bit is “1,” an MSK mark as a bit sync bs disposed at the front isfollowed by an MSK mark after 12 wobble sections.

As shown in FIG. 20C, in the wobble waveform pattern when a value of anADIP bit is “0,” an MSK mark as a bit sync bs disposed at the front isfollowed by an MSK mark after 14 wobble sections.

Thus, MSK modulation data is recorded in the wobbling groove. An addressformat of the ADIP information thus recorded is as shown in FIG. 21.

FIG. 21 illustrates a method of error correction for ADIP addressinformation.

The ADIP address information has 36 bits, to which 24 parity bits areadded.

The ADIP address information of 36 bits has 3 layer number bits (a layerno. bit 0 to a layer no. bit 2) for multilayer recording, 19 bits (anRUB no. bit 0 to a layer no. bit 18) for an RUB (recording unit block),and 2 bits (an address no. bit 0 and an address no. bit 1) for the threeaddress blocks of one RUB.

Further, 12 bits are provided as AUX data such as a disc ID forrecording recording conditions such as recording and reproducing laserpower and the like.

The ECC unit of the address data is thus a unit of a total of 60 bits,and comprises 15 nibbles (1 nibble=4 bits) Nibble 0 to Nibble 14, asshown in FIG. 21.

The parity bits are stored as inverted bits.

The error correction method is a nibble-based Reed-Solomon code RS (15,9, 7) with 4 bits as one symbol. That is, code length is 15 nibbles,data is 9 nibbles, and parity is 6 nibbles.

2. Disk Drive Apparatus

A disk drive apparatus capable of performing recording/reproduction ofthe disk as described above will next be described.

FIG. 22 shows a configuration of the disk drive apparatus.

A disk 100 in FIG. 22 is the above-described disk according to thepresent embodiment.

The disk 100 is loaded onto a turntable not shown in the figure, and isdriven by a spindle motor (SPM) 2 to be rotated at a constant linearvelocity (CLV) at the time of recording/reproducing operation.

Then an optical pickup 1 reads ADIP information embedded as wobbling ofa groove track in an RW zone on the disk 100. The optical pickup 1 alsoreads prerecorded information embedded as wobbling of the groove trackin a PB zone.

At the time of recording, the optical pickup records user data as phasechange marks on the track in the RW zone. At the time of reproduction,the optical pickup reads the phase change marks recorded by the opticalpickup.

Formed within the optical pickup 1 are: a laser diode serving as a laserlight source; a photodetector for detecting reflected light; anobjective lens at an output end of laser light; and an optical system(not shown) for irradiating a recording surface of the disk with thelaser light via the objective lens and guiding the reflected light tothe photodetector.

The laser diode outputs a so-called blue laser with a wavelength of 405nm. An NA of the optical system is 0.85.

The objective lens within the optical pickup 1 is held by a two-axismechanism so as to be movable in a tracking direction and a focusdirection.

The optical pickup 1 as a whole is movable in a direction of the radiusof the disk by a sled mechanism 3.

The laser diode in the optical pickup 1 is driven by a drive signal(drive current) from a laser driver 13 to emit laser light.

The photodetector detects information as the light reflected from thedisk 100, converts the information into an electric signal correspondingto an amount of light received, and then supplies the electric signal toa matrix circuit 4.

The matrix circuit 4 has a current-voltage conversion circuit, a matrixcalculation/amplification circuit and the like for output currents froma plurality of light receiving elements as the photodetector. The matrixcircuit 4 generates necessary signals by matrix calculation processing.

For example, the matrix circuit 4 generates a high-frequency signal(reproduced data signal) corresponding to reproduced data, a focus errorsignal and a tracking error signal for servo control, and the like.

Further, the matrix circuit 4 generates a push-pull signal as a signalrelated to the wobbling of the groove, that is, a signal for detectingwobbling.

The reproduced data signal outputted from the matrix circuit 4 issupplied to a reader/writer circuit 5; the focus error signal and thetracking error signal are supplied to a servo circuit 11; and thepush-pull signal is supplied to a wobble circuit 8.

The reader/writer circuit 5 subjects the reproduced data signal tobinarization processing, reproduced clock generation processing by a PLLand the like, thereby reproduces data read as phase change marks, andthen supplies the data to a modulating and demodulating circuit 6.

The modulating and demodulating circuit 6 has a functional part as adecoder at the time of reproduction and a functional part as an encoderat the time of recording.

At the time of reproduction, as decode processing, the modulating anddemodulating circuit 6 demodulates a run length limited code on thebasis of a reproduced clock.

An ECC encoder/decoder 7 performs ECC encode processing that adds errorcorrection codes at the time of recording and ECC decode processing forerror correction at the time of reproduction.

At the time of reproduction, the ECC encoder/decoder 7 captures the datademodulated by the modulating and demodulating circuit 6 into aninternal memory, then performs error detection/correction processing,deinterleaving processing and the like, and thereby obtains reproduceddata.

The data decoded to the reproduced data by the ECC encoder/decoder 7 isread and transferred to an AV (Audio-Visual) system 20 on the basis ofan instruction from a system controller 10.

The push-pull signal outputted from the matrix circuit 4 as the signalrelated to the wobbling of the groove is processed in the wobble circuit8. The push-pull signal as ADIP information is subjected to MSKdemodulation in the wobble circuit 8, thereby demodulated into a datastream constituting ADIP addresses, and then supplied to an addressdecoder 9.

The address decoder 9 decodes the data supplied thereto, thereby obtainsan address value, and then supplies the address value to the systemcontroller 10.

Also, the address decoder 9 generates a clock by PLL processing using awobble signal supplied from the wobble circuit 8, and supplies the clockto various parts as an encode clock at the time of recording, forexample.

A push-pull signal as the prerecorded information from the PB zone, asthe push-pull signal outputted from the matrix circuit 4 as the signalrelated to the wobbling of the groove, is subjected to processing of aband-pass filter in the wobble circuit 8, and is then supplied to thereader/writer circuit 5. The push-pull signal is binarized as in thecase of phase change marks, and thereby converted into a data bitstream. The data bit stream is ECC-decoded and deinterleaved by the ECCencoder/decoder 7, whereby data as the prerecorded information isextracted. The extracted prerecorded information is supplied to thesystem controller 10.

The system controller 10 can perform various setting processing, copyprotect processing and the like on the basis of the read prerecordedinformation.

At the time of recording, recording data is transferred from the AVsystem 20. The recording data is supplied to the memory in the ECCencoder/decoder 7 to be buffered.

In this case, as processing for encoding the buffered recording data,the ECC encoder/decoder 7 performs addition of error correction codes,interleaving, and addition of subcodes and the like.

The ECC-encoded data is subjected to RLL (1-7) PP modulation in themodulating and demodulating circuit 6, and then supplied to thereader/writer circuit 5.

As described above, the clock generated from the wobble signal is usedas the encode clock serving as a reference clock for the above encodeprocessing at the time of recording.

The recording data generated by the encode processing is supplied to thelaser driver 13 as a laser drive pulse after as recording compensationprocessing, the reader/writer circuit 5 adjusts a laser drive pulsewaveform and finely adjusts optimum recording power, for example, tocharacteristics of a recording layer, spot shape of the laser light,recording linear velocity and the like.

The laser driver 13 provides the laser drive pulse supplied thereto tothe laser diode within the pickup 1 and thereby drives the laser diodeto emit laser light. Thereby pits (phase change marks) corresponding tothe recording data are formed on the disk 100.

The laser driver 13 has a so-called APC (Auto Power Control) circuit tocontrol laser output at a constant level without depending on thetemperature and the like while monitoring laser output power throughoutput of a laser power monitoring detector provided within the opticalpickup 1. Target values of the laser output at the time of recording andat the time of reproduction are supplied from the system controller 10,and the laser output level is controlled to be at the target values atthe time of recording and at the time of reproduction, respectively.

The servo circuit 11 generates various servo drive signals for focus,tracking, and the sled from the focus error signal and the trackingerror signal supplied from the matrix circuit 4, and thereby performsservo operation.

Specifically, the servo circuit 11 generates a focus drive signal and atracking drive signal in response to the focus error signal and thetracking error signal, to drive a focus coil and a tracking coil of thetwo-axis mechanism within the optical pickup 1. Thereby a tracking servoloop and a focus servo loop are formed by the pickup 1, the matrixcircuit 4, the servo circuit 11, and the two-axis mechanism.

In response to a track jump instruction from the system controller 10,the servo circuit 11 turns off the tracking servo loop and outputs ajump drive signal to thereby perform track jump operation.

The servo circuit 11 further generates a sled drive signal on the basisof a sled error signal obtained as a low-frequency component of thetracking error signal, access control from the system controller 10 andthe like, to drive the sled mechanism 3. Though not shown, the sledmechanism 3 has a mechanism formed by a main shaft for holding theoptical pickup 1, a sled motor, a transmission gear and the like. Bydriving the sled motor according to the sled drive signal, a requiredslide movement of the pickup 1 is effected.

A spindle servo circuit 12 effects control for CLV rotation of a spindlemotor 2.

The spindle servo circuit 12 obtains the clock generated by PLLprocessing on the wobble signal as information on current rotationalspeed of the spindle motor 2, and compares the information withpredetermined CLV reference speed information to thereby generate aspindle error signal.

At the time of data reproduction, the reproduced clock (clock as areference for decode processing) generated by the PLL within thereader/writer circuit 5 serves as the information on the currentrotational speed of the spindle motor 2. Hence, the spindle servocircuit 12 can also generate the spindle error signal by comparing thisinformation with the predetermined CLV reference speed information.

The spindle servo circuit 12 then outputs a spindle drive signalgenerated according to the spindle error signal to thereby perform theCLV rotation of the spindle motor 2.

Further, the spindle servo circuit 12 generates a spindle drive signalin response to a spindle kick/brake control signal from the systemcontroller 10 to thereby perform operations such as starting, stopping,accelerating, and decelerating the spindle motor 2.

The various operations of the servo system and the recording andreproducing system as described above are controlled by the systemcontroller 10 formed by a microcomputer.

The system controller 10 performs various processing in response tocommands from the AV system 20.

For example, when a write command is issued from the AV system 20, thesystem controller 10 first moves the optical pickup 1 to an addresswhere writing is to be performed. Then the system controller 10 makesthe ECC encoder/decoder 7 and the modulating and demodulating circuit 6subject data (such as audio data and video data of various systems suchfor example as MPEG2) transferred from the AV system 20 to the encodeprocessing as described above. A laser drive pulse is then supplied fromthe reader/writer circuit 5 to the laser driver 13 as described above,whereby recording is performed.

When a read command requesting transfer of certain data (MPEG2 videodata or the like) recorded on the disk 100 is supplied from the AVsystem 20, for example, the system controller 10 first effects seekoperation control aiming at an address specified. Specifically, thesystem controller 10 issues a command to the servo circuit 11 to effectaccess operation of the optical pickup 1 targeting the address specifiedby a seek command.

Then, the system controller 10 effects operation control necessary totransfer data of the specified data section to the AV system 20.Specifically, the system controller 10 effects reading of the data fromthe disk 100, effects decoding/buffering and the like in thereader/writer circuit 5, the modulating and demodulating circuit 6, andthe ECC encoder/decoder 7, and then transfers the requested data.

At the time of recording and reproduction of the data by phase changemarks, the system controller 10 controls access and recording andreproducing operation using ADIP addresses detected by the wobblecircuit 8 and the address decoder 9.

Also, at a predetermined time such as a time of loading of the disk 100or the like, the system controller 10 effects reading of prerecordedinformation recorded as a wobbling groove in the PB zone of the disk100.

In this case, the system controller 10 first effects seek operationcontrol aiming at the PB zone.

Specifically, the system controller 10 issues a command to the servocircuit 11 to make the pickup 1 access the innermost circumference sideof the disk.

Then, the system controller 10 makes the pickup 1 perform reproductiontracing, thereby obtains a push-pull signal as reflected lightinformation, effects decode processing by the wobble circuit 8, thereader/writer circuit 5, and the ECC encoder/decoder 7, and then obtainsreproduced data as the prerecorded information.

On the basis of the prerecorded information thus read, the systemcontroller 10 performs laser power setting, copy protect processing andthe like.

At the time of reproduction of the prerecorded information in the PBzone, the system controller 10 controls access and reproducing operationusing address information included in a BIS cluster of the readprerecorded information.

While the disk drive apparatus in the example of FIG. 22 is connected tothe AV system 20, the disk drive apparatus according to the presentinvention may be connected to for example a personal computer or thelike.

Further, there can be an embodiment in which the disk drive apparatus isnot connected to another apparatus. In such a case, an operation unitand a display unit are provided, and the configuration of an interfacepart for data input and output is different from that of FIG. 22. Thatis, it suffices to perform recording and reproduction in response to anoperation by a user and form a terminal part for inputting andoutputting various data.

Of course, various other configuration examples are conceivable; forexample, an example as a recording-only apparatus or a reproduction-onlyapparatus is conceivable.

A method of MSK demodulation for a push-pull signal as ADIP informationin the wobble circuit 8 will be described with reference to FIG. 23 andFIGS. 24A to 24G.

As shown in FIG. 23, as a configuration for MSK demodulation, the wobblecircuit 8 has band-pass filters (BPF) 51 and 52, a multiplier 53, alow-pass filter (LPF) 54, and a slicer 55.

As described above, address data as ADIP information as shown in FIG.24A, for example, is converted into precoded data subjected todifferential encoding as shown in FIG. 24B, and then subjected to MSKmodulation as shown in FIG. 24C. On the basis of the MSK modulatedsignal, the groove is wobbled on the disk.

Therefore, information obtained as a push-pull signal at the time ofrecording and reproduction in the RW zone of the disk 100 is a signalcorresponding to the MSK modulated waveform of FIG. 24C.

A push-pull signal P/P supplied as a signal related to wobbling from thematrix circuit 9 in FIG. 22 is supplied to each of the band-pass filters51 and 52 in FIG. 23.

The band-pass filter 51 has a characteristic of passing bandscorresponding to a carrier frequency and a frequency 1.5 times thecarrier frequency. The band-pass filter 51 extracts a wobble component,that is, the MSK modulated wave of FIG. 24C.

The band-pass filter 52 has a narrower-band characteristic of passingonly a carrier frequency component. The band-pass filter 52 thusextracts the carrier component of FIG. 24D.

The multiplier 53 multiplies the outputs of the band-pass filters 51 and52 together. That is, synchronous detection can be performed bymultiplying the MSK modulated wobble signal and the carrier together,whereby a demodulated signal demod out of FIG. 24E is obtained.

The demodulated signal demod out is passed through the next LPF 54,whereby an LPF out signal of FIG. 24F is obtained.

The LPF 54 is for example a 27-tap FIR filter with the followingcoefficients:

-   −0.000640711-   −0.000865006-   0.001989255-   0.009348803-   0.020221675-   0.03125-   0.040826474-   0.050034929-   0.05852149-   0.065960023-   0.072064669-   0.076600831-   0.079394185-   0.080337385; Center-   0.079394185-   0.076600831-   0.072064669-   0.065960023-   0.05852149-   0.050034929-   0.040826474-   0.03125-   0.020221675-   0.009348803-   0.001989255-   −0.000865006-   −0.000640711

The LPF out signal obtained from the LPF 54 is binarized by the slicer55 formed as a comparator, whereby demodulated data (demod data) of FIG.24G is obtained.

The demodulated data (demod data) as a binarized output is channel bitdata forming address information. The demodulated data is supplied tothe address decoder 9 shown in FIG. 22, so that an ADIP address isdecoded.

3. Disk Manufacturing Method

A method of manufacturing the disk according to the present embodimentdescribed above will next be described.

A disk manufacturing process is roughly divided into a so-calledmastering process and a replication process. The mastering processcovers steps up to completion of a metallic master (stamper) used in thereplication process. The replication process mass-produces duplicateoptical disks using the stamper.

Specifically, the mastering process performs so-called cutting in whicha photoresist is coated on a polished glass substrate, and pits andgrooves are formed by exposing the photosensitive film to a laser beam.

In the case of the present embodiment, a groove wobbling on the basis ofprerecorded information is cut in a portion corresponding to the PB zoneon the innermost circumference side of the disk, and a groove wobblingon the basis of ADIP addresses is cut in a portion corresponding to theRW zone.

The prerecorded information to be recorded is prepared in a preparatoryprocess referred to as premastering.

After the cutting is completed, predetermined processing such asdevelopment and the like is performed, and then information istransferred onto a metallic surface by electroforming, for example, tocreate a stamper required when replicating the disk.

Then, the information is transferred onto a resin substrate by aninjection method, for example, using the stamper, a reflective film isformed thereon, and thereafter processing of machining into a requireddisk shape and the like is performed, whereby a final product iscompleted.

As shown in FIG. 25, for example, a cutting apparatus has a prerecordedinformation generating unit 71, an address generating unit 72, a switchunit 73, a cutting unit 74, and a controller 70.

The prerecorded information generating unit 71 outputs the prerecordedinformation prepared in the premastering process.

The address generating unit 7;2 sequentially outputs values as absoluteaddresses.

The cutting unit 74 includes: an optical unit (a laser light source 82,a modulating unit 83, and a cutting head unit 84) for irradiating aphotoresist-coated glass substrate 101 with a laser beam and therebyperforming cutting; a substrate rotating/shifting unit 85 for rotationdriving and slide shifting of the glass substrate 101; a signalprocessing unit 81 for converting input data to recording data andsupplying the recording data to the optical unit; and a sensor 86 forenabling determination of whether a cutting position is in the PB zoneor in the RW zone from a position of the substrate rotating/shiftingunit 85.

The optical unit includes: a laser light source 82 formed by an He—Cdlaser, for example; a modulating unit 83 for modulating light emittedfrom the laser light source 82 on the basis of the recording data; and acutting head unit 84 for condensing the modulated beam from themodulating unit 83 and irradiating a photoresist surface of the glasssubstrate 101 with the modulated beam.

The modulating unit 83 includes: an acoustooptic type optical modulator(AOM) for turning on/off the light emitted from the laser light source82; and an acoustooptic type optical deflector (AOD) for deflecting thelight emitted from the laser light source 82 on the basis of a wobblegenerating signal.

The substrate rotating/shifting unit 85 comprises: a rotating motor forrotation-driving the glass substrate 101; a detecting unit (FG) fordetecting rotational speed of the rotating motor; a slide motor forsliding the glass substrate 101 in a direction of the radius of theglass substrate 101; and a servo controller for controlling therotational speed of the slide motor and the rotating motor, tracking ofthe cutting head unit 84 and the like.

The signal processing unit 81 performs formatting processing for addingfor example error correction codes and the like to the prerecordedinformation and address information supplied via the switch unit 73, forexample, and thereby forming input data, and performs modulating signalgenerating processing for subjecting the formatted data to predeterminedcalculation processing and thereby forming a modulating signal.

The signal processing unit 81 also performs driving processing fordriving the optical modulator and the optical deflector of themodulating unit 83 on the basis of the modulating signal.

At the time of cutting, the substrate rotating/shifting unit 85 in thecutting unit 74 rotation-drives the glass substrate 101 at a constantlinear velocity and slides the glass substrate 101 while rotating theglass substrate 101 so that a spiral track is formed at a predeterminedtrack pitch.

At the same time, the light emitted from the laser light source 82 isconverted via the modulating unit 83 into a modulated beam on the basisof the modulating signal from the signal processing unit 81, and thenapplied from the cutting head unit 84 to the photoresist surface of theglass substrate 71. As a result, the photoresist is exposed to light onthe basis of the data and grooves.

The controller 70 controls performance of operation at the time of suchcutting by the cutting unit 74, and controls the prerecorded informationgenerating unit 71, the address generating unit 72, and the switch unit73 while monitoring a signal from the sensor 86.

At the time of a start of cutting, the controller 70 sets a slideposition of the substrate rotating/shifting unit 85 to an initialposition so that the cutting head unit 84 of the cutting unit 74 startslaser irradiation at an innermost circumference side. Then thecontroller 70 makes the substrate rotating/shifting unit 85 startrotation-driving the glass substrate 101 at a CLV and sliding the glasssubstrate 101 to form a groove with a track pitch of 0.35 μm.

In this state, the controller 70 makes the prerecorded informationgenerating unit 71 output prerecorded information and supply theprerecorded information to the signal processing unit 81 via the switchunit 73. Further, the controller 70 starts laser output from the laserlight source 82, and the modulating unit 83 modulates the laser light onthe basis of the modulating signal, or an FM code modulating signal ofthe prerecorded information, from the signal processing unit 81, wherebythe groove is cut into the glass substrate 101.

Thereby the groove as shown in FIG. 3B is cut in a region correspondingto the PB zone.

When the controller 70 thereafter detects from the signal of the sensor86 that the cutting operation has advanced to a position correspondingto the PB zone, the controller 70 switches the switch unit 73 to theaddress generating unit 72 side, and instructs the address generatingunit 72 to sequentially generate address values.

Also, the controller 70 lowers the sliding speed of the substraterotating/shifting unit 85 so as to form a groove with a track pitch of0.32 μm.

Thereby the address information is supplied from the address generatingunit 72 to the signal processing unit 81 via the switch unit 73. Thenthe laser light from the laser light source 82 is modulated in themodulating unit 83 on the basis of the modulating signal, or an MSKmodulating signal of the address information, from the signal processingunit 81. The groove is cut into the glass substrate 101 by the modulatedlaser light.

Thereby the groove as shown in FIG. 3A is cut in a region correspondingto the RW zone.

When the controller 70 detects from the signal of the sensor 86 that thecutting operation has reached an end of the read-out zone, thecontroller 70 ends the cutting operation.

As a result of such operation, a portion exposed to light which portioncorresponds to the wobbling grooves of the PB zone and the RW zone isformed on the glass substrate 101.

Thereafter development, electroforming and the like are performed tocreate a stamper, and the above-described disk is manufactured using thestamper.

While the disk according to the embodiment, and the disk drive apparatusand the disk manufacturing method provided for the disk have beendescribed above, the present invention is not limited to these examplesand various modifications thereof can be considered without departingfrom the scope of the subject matter.

INDUSTRIAL APPLICABILITY

As described above, with the disk recording medium, the disk driveapparatus, the reproducing method, and the disk manufacturing methodaccording to the present invention, the disk recording medium issuitable as a large-capacity disk recording medium, and great effectsare obtained in that the disk drive apparatus is improved in recordingand reproducing operation performance and the wobble processing circuitsystem may be a simple one.

1. A disk recording medium having a groove, said groove being formed ina spiral fashion to form a track on the disk, said disk recording mediumcomprising: a recording and reproducing area in which addressinformation is recorded by wobbling of said groove and the track formedby said groove is used for recording and reproducing mark information;and a reproduction-only area in which prerecorded information isrecorded by wobbling of said groove, wherein as a synchronizing signalof said prerecorded information, said prerecorded information has aplurality of synchronizing signals; each of said synchronizing signalscomprises a pattern out of rules of modulation of said prerecordedinformation and an identification pattern for identifying thesynchronizing signal; and said identification pattern is obtained bymodulating an identification number and an even parity bit of theidentification number by an FM code.
 2. A disk recording medium asclaimed in claim 1, wherein: recording linear density of saidprerecorded information recorded in said reproduction-only area is lowerthan recording linear density of said mark information recorded in saidrecording and reproducing area and is higher than recording lineardensity of said address information recorded in said recording andreproducing area.
 3. A disk recording medium as claimed in claim 1,wherein: the track formed by the groove in said reproduction-only areais not used for recording and reproducing mark information.
 4. A diskrecording medium as claimed in claim 1, wherein: said prerecordedinformation is copy protect information.
 5. A disk recording medium asclaimed in claim 1, wherein: said prerecorded information is recorded bywobbling said groove on the basis of an FM code modulated signal.
 6. Adisk recording medium as claimed in claim 1, wherein: an errorcorrection code format of said prerecorded information uses a same codeand structure as an error correction code format of said markinformation.
 7. A disk recording medium as claimed in claim 1, wherein:error correction code including address information is added to saidprerecorded information.
 8. A disk drive apparatus for recording andreproducing data on a disk recording medium, said disk recording mediumhaving a groove formed in a spiral fashion to form a track on the disk,and said disk recording medium including: a recording and reproducingarea in which address information is recorded by wobbling of said grooveand the track formed by said groove is used for recording andreproducing phase change mark information; and a reproduction-only areain which prerecorded information is recorded by wobbling of said groove,said disk drive apparatus comprising: head means for irradiating saidtrack with a laser and obtaining a reflected light signal; wobblingextracting means for extracting a signal related to wobbling of saidtrack from said reflected light signal; phase change mark informationextracting means for extracting a signal related to the phase changemark information from said reflected light signal; address decodingmeans for performing minimum shift keying (MSK) demodulation of saidsignal related to the wobbling extracted by said wobbling extractingmeans and decoding said address information at a time of reproduction insaid recording and reproducing area; phase change mark decoding meansfor decoding said signal related to the phase change mark informationextracted by said phase change mark information extracting means andthereby obtaining information recorded as the phase change markinformation at the time of the reproduction in said recording andreproducing area; and prerecorded information decoding means fordecoding said signal related to the wobbling extracted by said wobblingextracting means and thereby obtaining said prerecorded information at atime of reproduction in said reproduction-only area.
 9. A disk driveapparatus as claimed in claim 8, characterized in that: said prerecordedinformation decoding means obtains copy protect information.
 10. A diskdrive apparatus as claimed in claim 8, characterized in that: saidprerecorded information is recorded on said disk recording medium bywobbling said groove on the basis of an FM code modulated signal; andsaid prerecorded information decoding means obtains a data bit as saidprerecorded information by FM code demodulation processing.
 11. A diskdrive apparatus as claimed in claim 8, characterized in that: an errorcorrection code format of said prerecorded information uses a same codeand structure as an error correction code format of said phase changemark information; and said phase change mark decoding means and saidprerecorded information decoding means perform error correction decodingby an identical error correction circuit.
 12. A disk drive apparatus asclaimed in claim 8, characterized in that: error correction codeincluding address information is added to said prerecorded information;and at the time of the reproduction in said reproduction-only area,access operation is performed on the basis of the address informationextracted by said prerecorded information decoding means.
 13. Areproducing method for a disk recording medium, said disk recordingmedium having a groove formed in a spiral fashion to form a track on thedisk, and said disk recording medium including: a recording andreproducing area in which address information is recorded by wobbling ofsaid groove and the track formed by said groove is used for recordingand reproducing phase change mark information; and a reproduction-onlyarea in which prerecorded information is recorded by wobbling of saidgroove, said reproducing method comprising the steps of: at a time ofreproduction in said recording and reproducing area, extracting a signalrelated to wobbling of said track and a signal related to the phasechange mark information from a reflected light signal obtained when saidtrack is irradiated with a laser, performing minimum shift keying (MSK)demodulation of the extracted said signal related to the wobbling anddecoding said address information, and decoding the extracted saidsignal related to the phase change mark information and therebyobtaining information recorded as the phase change mark information; andat a time of reproduction in said reproduction-only area, extracting asignal related to wobbling of said track from a reflected light signalobtained when said track is irradiated with a laser, decoding theextracted said signal related to the wobbling and thereby obtaining saidprerecorded information.
 14. A reproducing method as claimed in claim13, characterized in that: at the time of the reproduction in saidreproduction-only area, copy protect information is obtained as saidprerecorded information.
 15. A reproducing method as claimed in claim13, characterized in that: said prerecorded information is recorded onsaid disk recording medium by wobbling said groove on the basis of an FMcode modulated signal; and at the time of the reproduction in saidreproduction-only area, a data bit as said prerecorded information isobtained by FM code demodulation processing on the extracted said signalrelated to the wobbling.
 16. A reproducing method as claimed in claim13, characterized in that: an error correction code format of saidprerecorded information uses a same code and structure as an errorcorrection code format of said phase change mark information; and errorcorrection decoding is performed by an identical error correctioncircuit in decoding said signal related to the phase change markinformation extracted at the time of the reproduction in said recordingand reproducing area and decoding said signal related to the wobblingextracted at the time of the reproduction in said reproduction-onlyarea.
 17. A reproducing method as claimed in claim 13, characterized inthat: error correction code including address information is added tosaid prerecorded information; and at the time of the reproduction insaid reproduction-only area, access operation is performed on the basisof the address information extracted by decoding said signal related tothe wobbling.
 18. A disk manufacturing method comprising the steps of:forming a groove in a spiral fashion to form a track on a disk; forminga reproduction-only area by forming said groove as a groove wobbled onthe basis of prerecorded information; and forming a recording andreproducing area by forming said groove as a groove wobbled on the basisof address information and using the track formed by said groove forrecording and reproducing mark information, wherein as a synchronizingsignal of said prerecorded information, said prerecorded information hasa plurality of synchronizing signals; each of said synchronizing signalscomprises a pattern out of rules of modulation of said prerecordedinformation and an identification pattern for identifying thesynchronizing signal; and said identification pattern is obtained bymodulating an identification number and an even parity bit of theidentification number by an FM code.
 19. A disk manufacturing method asclaimed in claim 18, wherein: recording linear density of saidprerecorded information recorded in said reproduction-only area is lowerthan recording linear density of said mark information recorded by usingsaid recording and reproducing area and is higher than recording lineardensity of said address information recorded in said recording andreproducing area.
 20. A disk manufacturing method as claimed in claim18, wherein: said prerecorded information is copy protect information.21. A disk manufacturing method as claimed in claim 18, wherein: saidprerecorded information is recorded by wobbling said groove on the basisof an FM code modulated signal of said prerecorded information.
 22. Adisk manufacturing method as claimed in claim 18, wherein: an errorcorrection code format of said prerecorded information uses a same codeand structure as an error correction code format of said markinformation recorded by using said recording and reproducing area.
 23. Adisk manufacturing method as claimed in claim 18, wherein: errorcorrection code including address information is added to saidprerecorded information.